The United States is in the midst of a troop withdrawal that will see American forces reduced to 50,000 by month's end from about 160,000 at their peak. When the drawdown is complete, America's seven-and-a-half year combat mission in Iraq will be over. The remaining troops will advise and train Iraqi security forces.

In an exclusive interview, Odierno said he was both confident in the abilities of Iraqi forces, but cautious about the long-term impact of the Iraq war on the Middle East and beyond.

When asked if the war was "worth" the all the sacrifice, the general said, "My answer to that question is: it's still yet to be determined."

His assessment was that it take "three to five years" to know if the Iraq war has brought more stability to the Middle East and, by extension, to the United States. "What I'm saying is the result we'll know in three to five years," Odierno said.

Withdrawal on scheduleThe commanding general said religious and ethnic divides in the Middle East, the strength and capability of Iraq's government and the behavior of Iraq's neighbors will all ultimately determine if the Iraq war was successful and therefore worth the sacrifice.

"That will be the ultimate determiner of how successful we were," he said.

In the short term, Odierno said he is confident that Iraq will not slip back into sectarian violence and that Iraqi security forces are ready to assume greater authority. The general said the withdrawal schedule for American combat forces is on track.

On Wednesday, Odierno briefed President Obama and his National Security Council about the Iraq pullout, telling the president that July was the third least violent month in Iraq since January 2004.

Violence has fallen sharply since the peak of sectarian warfare in 2006-2007, when thousands of Iraqis were killed in bloodletting between majority Shiite and Sunni Muslims.

As Iraqis began observing the Muslim holy month of Ramadan, U.S. officials said they expect an uptick in violence, with al-Qaida insurgents trying to exploit the failure of political factions to agree on a new government after March’s parliamentary election.